NULL pointer dereference in OpenSSL

CVE-2023-0401

A NULL pointer can be dereferenced when signatures are being verified on PKCS7 signed or signedAndEnveloped data. In case the hash algorithm used for the signature is known to the OpenSSL library but the implementation of the hash algorithm is not available the digest initialization will fail. There is a missing check for the return value from the initialization function which later leads to invalid usage of the digest API most likely leading to a crash. The unavailability of an algorithm can be caused by using FIPS enabled configuration of providers or more commonly by not loading the legacy provider. PKCS7 data is processed by the SMIME library calls and also by the time stamp (TS) library calls. The TLS implementation in OpenSSL does not call these functions however third party applications would be affected if they call these functions to verify signatures on untrusted data.

EPSS: 0.018 (77.9th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2023-0401?
CVE-2023-0401 is a high-severity vulnerability in OpenSSL, classified under NULL Pointer Dereference. CVSS score: 7.5/10. Published 2023-02-08.
How severe is CVE-2023-0401?
High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2023-0401 known to be exploited?
8 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.